Hi, FFJ:
My opinion is that could be a timming failure, probably the time chain and respective sprockets has been changed, this problem can be checked and fixed for you, if you has enough time and tools and some manual repair (i.e Chiltonīs) this chain is located front of the motor behind de water pump, there exist some marks on the sprockets and should be placed in correct position; this problems ocurres when chains is to loose for normal use or the engine has been exposed to high rpm regime. Normally you only needs to pay for some gaskets and labour, there exist a some procedures to check this condition checking the distributor.